The present invention relates to an RF (radio frequency) power amplifier and more particularly to an RF power amplifier with a modulating facility wherein the modulating signal is pre-emphasized so that the amplifier output signal has the desired shape.
An RF power amplifier of this kind is known from an article by S. Bayer, "R-F Power Amplifier System Solves Linearity Problems", Microwave Systems News, May-June 1971.
That article refers to amplitude modulation in general. No reference is made to modulation of the RF carrier wave by pulses, which is also an amplitude modulation of the RF carrier wave. The teaching contained in that article for controlling the modulating signal as a function of the amplifier output signal is not readily applicable to RF power amplifiers in which the RF carrier wave is modulated by pulses. This is true particularly if the pulses have only a short width (e.g. 8 .mu.s (microseconds)). The time required with the known method of control is too long for such applications.